<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <script src="./vue.js"></script>
    <script>
        window.onload=function(){
            Vue.filter('change',function(data){
                return data.toUpperCase()
            })
            new Vue({
                el:'#app',
                data:{
                    str:'hello',
                    str1:'HELLO'
                },
                methods:{},
                filters:{
                    'change1':function(data){
                        return data.toLowerCase()
                    }
                }
            })
        }
    </script>
</head>
<body>
    <div id="app">
        <h1>{{str | change}}</h1>
        <h1>{{str1 | change1}}</h1>
    </div>
</body>
</html>